Search

In most primate species, males transfer out of their natal groups, resulting in groups of unrelated males. However, in a few species, including humans, males remain in their groups and form life‐long associations with each other. This pattern of male philopatry is linked with cooperative male behaviors, including border patrols and predator defense. Because females in male‐philopatric species form weaker kin networks with each other than in female‐philopatric species, they are expected to evolve counter‐strategies to male sexual coercion that are relatively independent of support from other females. Studies of male‐philopatric nonhuman primates can provide insight into the evolutionary basis of prosocial behaviors, cooperation, and group action in humans and offer comparative models for understanding the sociality of other hominin species. This review will discuss patterns of dispersal and philopatry across primates, explore the resulting male and female behaviors, and argue that male‐philopatric nonhuman primate species offer insight into the social and sexual dynamics of hominins throughout evolution. [ABSTRACT FROM AUTHOR]

The intensity of sperm competition, in which sperm compete within the female reproductive tract to reach and fertilize her eggs, varies in species with different mating systems. Sperm competition is more intense in species where males cannot monopolize access to reproductive females and females mate with multiple males. In this scenario, a morphological change that increases the ability of sperm to reach and fertilize eggs should rapidly spread in the population, leading to sperm morphological differences between closely related species. Differences in sperm morphology have been reported among primate species with different mating systems. However, due to the inherent logistical and ethical difficulties to sample sperm from wild primates, the extent of variation in sperm morphology within species and among closely related species remains understudied. Here, we compared sperm morphological traits from two sister howler monkey species (Alouatta palliata and Alouatta pigra) that have different mating systems to investigate the effect of sperm competition on sperm morphological traits. We predicted that sperm from A. palliata, where females have more opportunities to mate with multiple males, would show differences in traits associated with increase sperm competitiveness compared to A. pigra where females mostly mate with the central male. We used linear mixed models to determine species differences in sperm morphology, controlling for individual variation. We found that midpieces and heads in A. palliata sperm were on average 26.2% and 11.0% longer, respectively, than those of A. pigra. Differences in these traits are important for sperm speed and hydrodynamic movement in other species and can affect fertilization success. This study provides empirical evidence of sperm morphological traits that evolved through sexual selection in sister primate species with different mating systems. Highlights: We collected sperm from wild Alouatta palliata and Alouatta pigra males to analyze sperm morphology. These sister species differ in mating system and gonadosomatic index, such that A. palliata has larger testis than A. pigra, suggesting more intense sperm competition.We analyzed 100 sperm cells per individual and computed 10 measurements from the head, midpiece, and tail for each sperm.We found significant differences in sperm head length and midpiece length between species. Sperm head and midpiece are longer in A. palliata. These traits have been associated with sperm swimming speed in other species.Our findings are consistent with the hypothesis that sperm competition is more intense in A. palliata than in A. pigra. [ABSTRACT FROM AUTHOR]

Negative interactions between humans and wildlife create one of the greatest threats to biodiversity conservation. When wild animals damage the crops in agricultural fields, subsistence farmers suffer food insecurity and economic instability. Animals can be killed or injured during these interactions, and communities may develop negative feelings about conservation. To address conservation concerns, projects should look at both sides of these interactions. A Participatory Action Research approach allows researchers and community members to work collaboratively to investigate and take action in response to this issue. Our team developed a community project to determine residents' perceptions of the benefits and costs of living around Kibale National Park, Uganda, and to implement changes to mitigate those costs. During our initial survey in 2015, we found that over 80% of our 114 respondents were subsistence farmers with no other source of income. All respondents felt that crop damage by wild animals was the biggest problem with living near the park, and they had negative feelings about the park and animals. Thus, we worked with project participants to establish the following land‐use changes throughout 2016 and 2017: (a) planting garlic as a cash crop, (b) planting tea as a buffer crop, (c) building beehive fences, and (d) maintaining a trench around the boundary of the park. Through monthly surveys, we assessed the success of these changes on reducing crop damage and improving conservation initiatives. Compliance with land‐use changes was significantly associated with a reduction in the events of crop damage, which has implications for economic stability and an individual's attitude about conservation. This project provides guidelines for using Participatory Action Research methods to develop sustainable interventions to improve human‐wildlife interactions. [ABSTRACT FROM AUTHOR]

ABSTRACT Behavioral flexibility allows primates to cope with environmental variability. Quantifying primate responses to human habitat modifications allows an effective means of assessing coping mechanisms. Within Kibale National Park, Uganda, logging led to reduced primate food availability that still exists almost 50 years after the harvest. Following the predictions of the ideal free distribution theory, primate densities are expected to decrease in areas of lower resource availability so that the resources available per individual are equivalent in logged and old-growth areas. However, counter to what would be predicted by the ideal free distribution theory, red colobus monkeys ( Procolobus rufomitratus) occur at similar densities in logged and old-growth areas of Kibale. This suggests that either the ecological differences between the two areas are not sufficient to impact red colobus densities or that animals in logged areas are compensating to changes in resource availability by using different foraging strategies. To test between these hypotheses, we examined four groups of red colobus, two in logged and two in old-growth forests, and compared feeding behavior, feeding tree size, and tree productivity. Females in logged areas fed on resources from a greater number of plant species, fed on fewer resources from each species, and spent more time feeding than those in old-growth areas. By expanding their diet, females in logged areas effectively increased the resources available to them, which may contribute to their ability to maintain similar densities to females in old-growth areas. These findings have implications for an evolutionary understanding of how species deal with environmental change and considerations for conservation practices that determine what areas should be prioritized for protection. Am J Phys Anthropol 154:52-60, 2014. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]